I am using pneumatic motor to run one of my project, how to stop the pneumatic motor precisely at the location I need when sensor detected. Now the motor is having momentum so there is around 20mm ~ 30mm displacement after the valve cut off. Using flow control valve can slow down motor, but motor not able to deliver torque needed.
This seems to be a question more related to the mechanics of the system than to the electronic control itself. The inertia of the movement is acting to different degrees at different points in the course. I do not believe you can achieve a satisfactory precision in a pneumatic system. Perhaps you should consider using a magnetic braker together with the control valve, but I'm unsure of the results.